MCQ Collection
MDCAT Chemistry MCQs
Practice MDCAT Chemistry questions with answers and explanations.
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Correct Answer: B. Reactants are strongly favored at equilibrium
Explanation:
A small K means little product is present at equilibrium.
The forward reaction may still occur.
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Correct Answer: C. A ratio with the equilibrium-expression form using current concentrations or pressures
Explanation:
Q can be calculated at any stage.
Comparing Q with K predicts the direction of net change.
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Correct Answer: D. Toward products
Explanation:
The mixture contains too little product relative to equilibrium.
Net forward reaction increases Q toward K.
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Correct Answer: A. Heat required to raise an object's temperature by one degree
Explanation:
Heat capacity depends on the amount and identity of matter.
Specific heat capacity is heat capacity per unit mass.
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Correct Answer: A. Toward reactants
Explanation:
The mixture contains too much product relative to equilibrium.
Net reverse reaction lowers Q toward K.
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Correct Answer: B. Measurement of heat changes
Explanation:
Calorimeters track temperature changes in known heat capacities.
They help determine reaction or phase-change energy.
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Correct Answer: B. How an equilibrium system responds to a disturbance
Explanation:
An equilibrium shifts to oppose an imposed change.
Changes in concentration, pressure, or temperature may shift position.
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Correct Answer: C. Overall enthalpy change is the sum of enthalpy changes for any reaction pathway
Explanation:
Enthalpy is a state function.
Therefore the path between initial and final states does not affect ΔH.
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Correct Answer: C. The equilibrium generally shifts toward products
Explanation:
The system consumes some added reactant.
The shift reduces the imposed concentration change.
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Correct Answer: D. Enthalpy change forming one mole of compound from elements in standard states
Explanation:
Standard formation enthalpies are tabulated reference values.
Elements in their standard states have ΔHf° defined as zero.
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Correct Answer: D. The equilibrium generally shifts toward products
Explanation:
The reaction produces more product to replace what was removed.
This is an application of Le Chatelier's principle.
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Correct Answer: A. Energy required to break one mole of specified gas-phase bonds
Explanation:
Bond enthalpies are average values for many molecules.
Breaking bonds requires energy, while forming bonds releases energy.
